Current Intel tx prepare function does not properly handle the
case where only IP checksum is requested, without requesting
any L4 checksum or TSO: IP checksum is not properly reset to 0
and output packet may contain invalid IP checksum.
Fixes: 4fb7e803eb ("ethdev: add Tx preparation")
Cc: stable@dpdk.org
Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>